1. Field of the Invention
This invention relates generally to seismic energy monitoring systems for underground mines and, more particularly, but not by way of limitation, it relates to an improved system for maintaining continual surveillance and record of the mine operation and general condition with attendant capability of mine position in the event of catastrophy.
2. Description of the Prior Art
Various attempts to derive meaningful subterranean information relative to mine activity or emergency location needs are present in the prior art. There have been devised many forms of electrically actuated indicator apparatus for conveying a particular condition from a substerranean mine location to a surface station thereby to provide alarm or warning when necessitated. Such systems, however, have been limited to an actively operable transmission type of link, whether by electric wire, radio wave propagation or voice tube. Still other teachings have long dwelled on the possibility of some form of sound locating apparatus wherein acoustic energy is surfacd-detected to derive either message information or underground location information, but in general such devices have been rudimentary in nature and deployed in non-uniform, unique manner for each given instance. The closest prior art known to applicants in U.S. Pat. No. 3,132,330 in the name of Donner entitled "Electric Alarm Systems". This system utilizes a plurality of ground-disposed geophones for detecting subsurface disturbances which are individually connected to a particular alarm device characteristic of a surface position. This device provides no meaningful data short of an all-out alarm condition which, in many cases, may be too late to be of value in correcting the situation.